Surgery often requires the formation of an opening within a body cavity that is to be operated on. Depending on the size of the opening, the healing of such an opening can require a lengthy recovery time. Moreover, a relatively large opening may leave a permanent scar on the skin, which is undesirable to patients.
To avoid forming relatively large openings in body cavities, minimally invasive surgery, e.g., laparoscopic surgery, is a current surgical technique in which operations are performed through a relatively small opening with diameters of about 0.5 mm to 10 mm. Such minimally invasive surgery provides the benefits of reduced pain and shorter recovery times.
Moreover, it is known that incisions smaller than about 3.0 mm greatly reduce the likelihood of permanent scarring. However, many tools required for surgery have dimensions greater than 3.0 mm and, therefore, cannot enter the body cavity through 3.0 mm openings. Therefore, the benefits of minimal scarring and even shorter recovery times cannot be realized in many surgeries.
Therefore, a need exists for a dilating cannula that is radially expandable both inside and outside of the opening to receive surgical tools that cannot fit within the formed opening without increasing the size of the incision or tearing other tissue in the body cavity.